#Blood test shows promise for early detection of dementia in people with a certain sleep disorder

For people with a certain sleep disorder, a simple blood test could help predict the development of dementia years before symptoms appear, a new study indicates.

Idiopathic REM sleep behavior disorder (iRBD) causes people to physically act out their dreams while sleeping. The disorder is also associated with a very high risk of Parkinson’s disease and a related condition called Dementia with Lewy Bodies. This is a form of dementia that often causes memory and cognitive loss, as well as vivid visual hallucinations and movement difficulties similar to Parkinson’s.

McGill University researchers have discovered that a blood test, originally developed to detect Alzheimer’s disease, could also identify which patients with the iRBD sleep disorder are most likely to develop Dementia with Lewy Bodies. The blood test analyzes two proteins in the blood that serve as biomarkers for Alzheimer’s.

“Detecting dementia risk early could have significant implications for how doctors guide patients, helping them plan for the future and potentially allowing for more personalized, effective treatments,” said Dr. Ronald Postuma, a Professor in McGill’s Department of Neurology and a clinical researcher at The Neuro (Montreal Neurological Institute-Hospital).

Researchers followed 150 iRBD patients, testing their blood for the biomarkers and tracking their health annually. Remarkably, the blood test, taken four years before, predicted dementia in almost 90 percent of the patients who later developed the disease.

Finding links between brain diseases

This study, published in the journal Brain, also suggests the early stages of Parkinson’s and Alzheimer’s have more in common than previously thought.

“Our findings suggest that Alzheimer’s treatments could also be tested in patients with this sleep disorder. Perhaps, if treatments start early enough, Dementia with Lewy Bodies can be prevented,” said first author Dr. Aline Delva, who was a research fellow at The Neuro during the study.

The research team plans to expand the study to confirm how well the test can predict dementia risk in patients with diagnosed Parkinson’s disease as well as other populations at risk for Dementia with Lewy Bodies.